Idelalisib is a phosphatidylinositol 3-kinase δ inhibitor (PI3Kδ inhibitor) developed by Gilead Sciences (USA) for treatment of chronic lymphocytic leukemia, indolent non-Hodgkin's lymphoma, mantle cell lymphoma, diffuse large B cell lymphoma, Hodgkin's lymphoma, multiple myeloma, acute myeloid leukemia and other hematological malignancies. The oral capsules are available in three strengths (100 mg, 150 mg and 300 mg). Idelalisib entered into a phase-III clinical study for treatment of chronic lymphocytic leukemia in 2012.
The chemical name of idelalisib is 5-fluoro-3-phenyl-2-[(S)-1-(9H-purin-6-ylamino)-propyl]-3H-quinazoline-4-one. Its English name is idelalisib or idelilisib. It is also known as GS-1101 or CAL-101. The chemical structural formula is shown below:

Example 9 in patent document WO2005113556A1 discloses idelalisib and a preparation process thereof. The disclosure of this patent document is hereby incorporated by reference in its entirety. Through repeated experiments, the inventors of the present invention discovered that the substance obtained according to the preparation process provided in WO2005113556A1 is a solvate of idelalisib with 0.4 molecule of ethanol (referred to as Form I in the present invention). However, the document did not provide characterization data of Form I. The inventors of the present invention discovered that Form I has the following defects: the weight change within the relative humidity range of 20˜80% is about 0.95%, indicating that the crystalline form has some hygroscopicity; Form I is not very stable.
Therefore, there remains a practical significance to develop novel crystalline polymorphic forms of idelalisib with more advantageous properties.